1. Field of the Invention
The invention relates to plastic bags, and particularly to bags fabricated of polyethylene or similar plastics for use as refuse bags and for other purposes. The invention is particularly concerned with the manner of closing and handling these bags as well as their method of manufacture.
2. Description of the Prior Art
Conventionally, large size plastic bags of this type are manufactured by extruding a tube of plastic, expanding the tube with air before the plastic is set, flattening the tube, forming transverse heat seals and adjacent perforations at equally spaced intervals, and rolling up the flattened tube for shipping purposes. The bags are removed one at a time by tearing them off the roll at the perforations.
When each bag is filled, it is necessary to close it by a separate tie. Examples of such ties are shown in Eichler U.S. Pat. No. 2,664,358 and Evans et al U.S. Pat. No. 3,512,700. The use of such ties is disadvantageous; it is necessary in each case to hold the bag closed with one hand while applying the tie with the other. The ties must be stored separately and can be misplaced. With overly full bags, they may be difficult to apply.
Various bag constructions have been proposed incorporating integral tie strips. Among these are Shvetz U.S. Pat. Nos. 3,186,626 and 3,217,971. These prior constructions have certain drawbacks, however. They require an additional act on the part of the handler in tearing away the integral tie strips from the remainder of the bag. They also substantially reduce the useful bag capacity and are not as effective as the present invention in holding the bag completely closed.
Erickson U.S. Pat. No. 3,441,198 shows a flexible bag for packaging foods having ears to facilitate handling as the food item is placed therein. This patent, however, is not believed to teach the claimed invention for reasons which will appear below.
In the bag manufacturing process described above, an intermediate step is often provided during which the sides of the tube are tucked in before the tube is flattened and rolled up, in order to reduce the package size. The illustrated embodiment of the invention is of particular advantage in this type of manufacturing operation.